Materials, such as yarn and webbing, which are roll wound on tubular cores are commonly stored and transported in pallet systems. A preferred type of pallet system comprises a base pallet upon which successive layers of vertically oriented rolls are stacked, respective layers being separated by intermediate panels or separator pads. A top panel is placed over the top layer of rolls. The assembly is then enveloped in shrink wrap or stretch wrap, the wrapping preferably covering all sides of the assembly including the top and bottom. Examples of such pallet systems are described in U.S. Pat. Nos. 4,580,680; 4,667,823; 4,998,619; and in European Application Publication No. 465815 A3 (Ser. No. 9118651.0). Compared to other types of pallet systems having more extensive frameworks, pallet systems as described above are relatively lightweight, inexpensive, recyclable, simple, and versatile. Further, the shrink wrap serves to protect the packages from environmental hazards such as contamination by dust and moisture.
Pallet systems as described above also have significant shortcomings, particularly when used to store and transport delicate goods such as yarns. In the absence of a supplemental framework, the forces created in shrink wrap or stretch wrap cause the file to contact the surface of the outer rolls of yarn. This contact damages the yarn resulting in significant degradation of the yarn quality. In the case of yarn having low denier, such degradation very often results in unacceptable breakage rates and poor dyeability which in turn causes significant manufacturing downtime and rejects.
Another shortcoming of prior art shrink wrap and stretch wrap pallet systems is their limited rigidity. While heavier and more tightly wrapped films may be used, there is an inherent limitation in the degree of rigidity that can be realized. A high degree of rigidity is often required or desired. For example, it is often desirable to stack pallet assemblies on top of one another. Moreover, the stresses involved in transporting package assemblies are often substantial.
In an attempt to overcome the aforementioned shortcomings of shrink wrapped and stretch wrapped pallet systems, such pallet systems have been provided with corner posts. Corner posts may serve to space the wrap from the yarn but do very little to stabilize the package. Furthermore, corner posts require a bulkier or more complicated return package (i.e., the pallet system in disassembled configuration for return to the supplier) and have short useful lives because of damage sustained in return. Corner posts significantly complicate the loading procedure requiring that four posts be held in place while the top panel is installed. Moreover, corner posts do not lend themselves to automation.
Thus, there exists a need for a supplemental framework for maintaining space between a shrink wrap or stretch wrap film of a pallet system and the rolls or packages loaded thereon. Further, there exists a need for such a framework which provides additional rigidity to the structure, particularly lateral rigidity. There exists a need for such a framework which does not significantly increase the size of the return package and which lends itself to automatic assembly.